Mask



FIG. 1 is a first front perspective view of a mask, showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top front perspective view thereof;

FIG. 7 is a second front perspective view thereof;

FIG. 8 is a bottom rear perspective view thereof;

FIG. 9 is a right side elevational view thereof; and,

FIG. 10 is a left side elevational view thereof.

The broken lines in the drawings depict portions of the mask that form no part of the claimed design. 

CLAIM The ornamental design for a mask, as shown and described. 